1. Field
The present disclosure relates generally to inspection systems and, in particular, to backscatter inspection systems. Still more particularly, the present disclosure relates to a method and apparatus for inspecting an object by moving a beam of radiation along the object in a selected pattern and detecting the backscatter formed in response to the beam encountering the object.
2. Background
Some currently available nondestructive inspection systems use radiation to inspect an object. The radiation may take the form of, for example, without limitation, x-rays, gamma rays, neutrons, or some other suitable type of radiation. A backscatter x-ray system is one example of a nondestructive inspection system that uses x-rays to inspect an object.
Some currently available backscatter x-ray systems include an x-ray tube, a collimator, and a detector system. The x-ray tube generates and emits x-rays. The collimator filters these x-rays to form an x-ray beam using the portion of the x-rays that travels parallel to a specified direction. This x-ray beam may be referred to as a pencil x-ray beam in some cases. During inspection of an object, the collimator is positioned such that the x-ray beam is directed toward the object.
When the x-ray beam encounters the object, some or all of the x-rays in the x-ray beam are scattered by the object. These scattered x-rays are referred to as backscatter. The detector system detects some or all of this backscatter. The detected backscatter may be used to generate image data for the object that can be used to form one or more images of the object. For example, the backscatter detected when the x-ray beam is directed at a particular location on the object may be used to generate a value for a pixel in an image that corresponds to that particular location on the object.
The x-ray beam may be moved along the object in a selected pattern such that image data may be generated for different locations on the object. This pattern may be, for example, a raster pattern. In particular, the x-ray beam may be oscillated along the object. Oscillating an x-ray beam includes moving the x-ray beam back and forth in a particular direction. The backscatter x-ray system may be mounted on a moveable platform that moves the backscatter x-ray system such that the x-ray beam may be oscillated in different directions substantially parallel to each other. The image data may then be used to form one or more images of the object. These images may be used to determine whether any inconsistencies are present in the object.
With some currently available backscatter x-ray systems, oscillating an x-ray beam along the object requires moving both the x-ray tube and the collimator at the same time independently of the moveable platform. In other words, moving the x-ray beam from one location on the object to another location on the object requires that both the collimator and the x-ray tube be moved. The number of components needed to move both the x-ray tube and the collimator such that the x-ray beam may be moved along the object in a selected pattern may be greater than desired with these currently available backscatter x-ray systems. Further, the weight and/or complexity of these types of backscatter x-ray systems may be greater than desired.
Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.